I exited while it was raining in-game, and I returned after an hour.
Upon return , I expected that it would still be raining and I did not think of it much.
However, I've noticed that the clouds were black, suggesting a thunderstorm is occurring, but when I tried to attack the lightning rod with the trident (enchanted with channeling), no lightning, and also, there were no mobs, when normally there are during a thunderstorm even at day and midday.
Another thing I saw, which made me feel there is something wrong, there was an Enderman, unharmed and perfectly fine during the rain.

Screenshot 163111: Enderman attacking me while i was in a 2x1 shade
Screenshot 163225: Enderman standing by the tree, completely unharmed by the rain.

Edit 1: Exiting and re-entering the world or entering another dimension and returning resolves the issue.